Staple gun



FIG. 1 is a perspective view of a staple gun showing my new design;

FIG. 2 is a front elevational view thereof; the opposite side being a mirror image of the shown.

FIG. 3 is a left elevational view thereof;

FIG. 4 is a right elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for staple gun, as shown and described. 